US3702962A - Ac to dc rectifier circuit with rapid turn-off in case of overcurrent through the load circuit - Google Patents

Ac to dc rectifier circuit with rapid turn-off in case of overcurrent through the load circuit Download PDF

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Publication number
US3702962A
US3702962A US196912A US3702962DA US3702962A US 3702962 A US3702962 A US 3702962A US 196912 A US196912 A US 196912A US 3702962D A US3702962D A US 3702962DA US 3702962 A US3702962 A US 3702962A
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United States
Prior art keywords
terminal
circuit
transformer
storage device
energy storage
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US196912A
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English (en)
Inventor
Rolf Wohr
Eckart Gotz
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication date
Priority claimed from DE19712100415 external-priority patent/DE2100415C3/de
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
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Publication of US3702962A publication Critical patent/US3702962A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/02—Conversion of AC power input into DC power output without possibility of reversal
    • H02M7/04—Conversion of AC power input into DC power output without possibility of reversal by static converters
    • H02M7/12—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/125—Avoiding or suppressing excessive transient voltages or currents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
    • B23H3/00—Electrochemical machining, i.e. removing metal by passing current between an electrode and a workpiece in the presence of an electrolyte
    • B23H3/02—Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions

Definitions

  • ABSTRACT A plurality of main rectifiers are connected to a transformer secondary with one terminal, the other terminal being connected to the load circuit.
  • a sensing circuit is provided to detect over-current conditions.
  • a rapid turn-off circuit is connected to provide reverse current to the rectifier elements, the rapid tum-off circuit being triggered by the sensing circuit and having a series connected control switch, typically a thyristor (SCR), an energy storage device (typically a condenser) and a pair of connections, one of which preferably includes a diode, and connects back to the load terminal of the main rectifier, the other connection, preferably including a smoothing choke, being connected back to the transformer, so that, when the thyristor is triggered, reverse current will be applied to the rectifier and, additionally, the thyristor will be held conductive by current through the transformer and the thyristor connection to the rectifiers.
  • SCR thyristor
  • an energy storage device typically a condenser
  • the present invention relates to a circuit to obtain direct current from alternating current, and having a group of main rectifier elements connected to the secondary of a transformer.
  • the circuit of the present invention is particularly useful with rectifier banks, to supply high level direct current output, for use in electroplating, or electrolytic deposition of metal.
  • To obtain effective deposition of metal it is customary to hold the distance between the work piece to' be plated, and the counter electrode, as small as possible.
  • An electrolyte typically an electrolyte liquid is then supplied under pressure to the space between the electrode and the workpiece. It is sometimes impossible to avoid minor variations in distances between the workpiece and the counter electrode. When this distance drops below a predetermined value, very high currents arise which, in an extreme case involving actual contact between electrode and work piece, may actually cause a short circuit.
  • Changes in distance between counter electrode and work piece may arise, for example, due to shocks or vibrations of the apparatus, variations in pressure on the electrolytic fluid, surface irregularities, or collection of conductive particles on the work piece or the counter electrode. It is therefore important that current supply be interrupted rapidly as soon as an overcurrent condition is detected, in order to prevent damage due to the excessive heating upon excessive localized current or, in an extreme, arcing.
  • the circuit of the present invention is, of course, also applicable for other uses.
  • the basic circuit of a transformer feeding a bank of rectifiers has a rapid tum-off circuit connected thereto, which includes a switching element, typically a thyristor (for example an SCR) which has a series connected condenser, the condenser being charged to a voltage which is high with respect to the load voltage, for example by an auxiliary source.
  • the condenser is then connected to a pair of connections, one leading to the terminal of the main rectifier elements connected to the load, and the other leading back to the transformer.
  • An overcurrent sensing circuit which fires the thyristor when an overcurrent condition is detected, permitting the charged energy storage condenser to discharge and provide counter current flow to the main rectifier element, thus reliably and rapidly interrupting current therethrough.
  • the thyristor is maintained in conductive condition by current through the second branch to the transformer, which preferably includes a smoothing choke, and to hold' the circuit turned off.
  • the circuit is simple, reliable, and requires few parts in addition to the normal rectifier circuit, while providing effective protection.
  • FIGURE is a schematic circuit diagram of a rectifier circuit with the protective circuit to rapidly turn ofi' the main rectifier bank.
  • a three-phase supply network 1 is connected over fuses 2, a main switch 3, to the primary 4 of a transformer 5.
  • the transformer has split secondary windings 6a, 6b, which are interconnected by a drainage coil 7.
  • Each of the secondary windings 6 is connected to the anode of a main rectifying thyristor 8, the cathodes of which are connected together.
  • the gates of the thyristors 8 are connected to a fire control circuit to phase the firing of the thyristors as desired. Such fire control circuits are well known and need not be described.
  • the cathodes of the thyristors are interconnected and are connected to the positive output 16 to which the load circuit is to be connected.
  • the negative terminal 17 for the load circuit is connected over a smoothing choke 18 to the drainage coil 7.
  • the rapid turn-off protective circuit includes a group of diodes 9, one each connected to the secondary 6a, 6b of the transformer and having their cathodes interconnected, to form together an OR-gate.
  • the common junction point of diodes 9 is connected to the anode of a thyristor 10, the cathode of which is connected in series to a storage condenser 11.
  • the other terminal of storage condenser 11 is connected to a junction and branches, on the one side, to the anode of a diode 12, the cathode of which is connected to the common connection of the thyristors 8.
  • the other side of the junction is connected back to the transformer, for example by being connected to the smoothing choke 18.
  • a charging circuit for condenser 1 1 is connected in parallel thereto and includes a source of direct current potential 13, a limiting resistor 15 and a switch 14.
  • a small resistance 19, forming a measuring resistance is connected in series between the common connection of the thyristors 8 and the load terminal 16.
  • a voltage U will be developed across resistance 19 which is sensed in a threshold detector 19a, connected thereacross, and providing an output pulse when the voltage drop U across resistance 19 exceeds a predetermined value, indicative of excessive load curto the current flowing through the load between ter-.
  • threshold detector 19a responds and applies a pulse to the gate circuit 10a of the thyristor 10.
  • the condenser 11 discharges through the condenser. lnitially, current will flow over diode l2 and in reverse over the then conductive thyristor 8, one of the diodes 9, and back tothe thyristor 10. The thyristor 8 will be effectively extinguished.
  • a portion of the discharge current from condenser 1 1 will flow over the second branch of the series circuit, that is, over smoothing choke 18 and into drainage coil 7 of transformer 5, and back to the secondary winding 6a, 6b respectively, and returning over diode 9 to thyristor 10.
  • This discharge of condenser 11 will continue even after the current through diode 12 stops, due to the blocking of thyristor 8, the cathode potential of the thyristors 8 being held positive with respect to theirranode potential longer than the conductive period normal for the specific thyristor. This reliably interrupts conduction of the thysistor and causes its rapid extinction.
  • the circuit will revert to conduction only after a short time delay, during which the switch 14 must be closed, to charge condenser l 1 to its full voltage.
  • the circuit of the present invention is simple and inexpensive,- and reliably and rapidly turns off the specific thyristor which is conductive at any one instance, as soon as current through the load circuit exceeds a predetermined value, for example, as soon as the current between a work piece and the counter electrode in an electrolytic plating bath increases beyond a safe value.
  • the transformer preferably has a drainage coil 7, but this is not a requirement.
  • Other transformers, and other rectifier circuits may be used, such as bridge connections, delta connections, star connections, or double star connections, as known in the art.
  • the OR gate formed by the diodes 9 connected to the thyristor 10 may be replaced by a group of thyristors 10, each having their gates connected to the terminal 10a of the threshold detector, thus decreasing the total number of components, at the cost, however, of increasing the number of the thyristors.
  • the diode 12 is not strictly necessary, if the commutation current for the thyristors is permitted to How over the load resistance, the branch then arising at the junction between choke 18 and terminal 17, 16 of the load. The thyristor switches off even more rapidly under such conditions, since the diode element, required to switch from blocked to conductive state, is not used.
  • AC to DC rectifier circuit with rapid turn off to prevent damage in case of excessive current through a load circuit having a a transformer adapted for connection to a source of AC;
  • main rectifier elements (8) connected to the secondary (6a, 6b) of the transformer and adapted to be successively conductive and connected to the load circuit;
  • a rapid turn-off circuit for the rectifiers comprising a series circuit including a controlled switching element (l0) having a control input (a) connected and responsive to the control output of the sensing means, the controlled switching element being connected to be normally non-conductive;
  • an energy storage device (11) having one terminal connected to the other terminal of the switching element
  • Circuit according to claim 1 wherein the other connection includes a smoothing choke (18). Circuit according to claim 1, wherein one terminal of the series connection is interconnected to one terminal, each, of the main rectifier elements.
  • Circuit according to claim 1 including an auxiliary energy source (13) and a switch (14) selectively interconnecting the auxiliary energy source with the energy storage device to charge the energy storage device.
  • the controlled switching element comprises a thyristor (10) having its main current path in normal current flow direction connected to the diode (9) and the energy storage device (11).
  • the second other terminal of the series circuit is connected to the transformer, and hence to the one terminal of the main rectifier elements.
  • one connection forming the one other terminal of the series circuit comprises a diode (12) connected in current flow direction to the energy storage device.
  • connection forming another terminal comprises a smoothing choke interconnecting the energy storage device and the thyristor to the transformer.
  • Circuit according to claim 1 including means charging the energy storage device to a voltage level which is high with respect to the voltage across the load circuit.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Mechanical Engineering (AREA)
  • Power Engineering (AREA)
  • Rectifiers (AREA)
  • Protection Of Static Devices (AREA)
US196912A 1971-01-07 1971-11-09 Ac to dc rectifier circuit with rapid turn-off in case of overcurrent through the load circuit Expired - Lifetime US3702962A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19712100415 DE2100415C3 (de) 1971-01-07 Überstromschutzeinrichtung zum schnellen Abschalten einer Gleichstromerzeugungsanlage

Publications (1)

Publication Number Publication Date
US3702962A true US3702962A (en) 1972-11-14

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ID=5795281

Family Applications (1)

Application Number Title Priority Date Filing Date
US196912A Expired - Lifetime US3702962A (en) 1971-01-07 1971-11-09 Ac to dc rectifier circuit with rapid turn-off in case of overcurrent through the load circuit

Country Status (8)

Country Link
US (1) US3702962A (enrdf_load_html_response)
JP (1) JPS4714624A (enrdf_load_html_response)
CH (1) CH546016A (enrdf_load_html_response)
FR (1) FR2121514B1 (enrdf_load_html_response)
GB (1) GB1373417A (enrdf_load_html_response)
IT (1) IT946332B (enrdf_load_html_response)
SE (1) SE372673B (enrdf_load_html_response)
SU (1) SU1003777A3 (enrdf_load_html_response)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3867669A (en) * 1974-01-11 1975-02-18 Yakov Lvovich Krasik Power source with a sparkproof output
US3931546A (en) * 1974-05-28 1976-01-06 C. E. Niehoff & Co. Over-voltage protection circuit
US4331994A (en) * 1979-09-28 1982-05-25 Borg-Warner Corporation Shootthrough fault protection system for a voltage source transistor inverter
US4428023A (en) 1980-02-25 1984-01-24 Bbc Brown, Boveri & Company Limited Electronic protective circuit
US4825029A (en) * 1987-06-02 1989-04-25 Wickes Companies, Inc. Spark erosion system for reducing the height of a honeycomb seal
US4853046A (en) * 1987-09-04 1989-08-01 Surface Combustion, Inc. Ion carburizing
US5127967A (en) * 1987-09-04 1992-07-07 Surface Combustion, Inc. Ion carburizing
US5241152A (en) * 1990-03-23 1993-08-31 Anderson Glen L Circuit for detecting and diverting an electrical arc in a glow discharge apparatus
WO1999014779A1 (de) * 1997-09-16 1999-03-25 Siemens Aktiengesellschaft Anordnung zur gewinnung einer hilfsenergie für ein auslösesystem und verwendung derselben
US5995394A (en) * 1997-10-10 1999-11-30 Asea Brown Boveri Ab Device for connecting a VSC converter to a source of alternating voltage
US6442051B1 (en) 2000-10-31 2002-08-27 General Electric Company Full thyristor bridge circuit with free wheeling diode for de-excitation control and stability sensing

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51156435U (enrdf_load_html_response) * 1975-06-09 1976-12-13
JPS5273161A (en) * 1975-12-15 1977-06-18 Naniwa Seitei Kk Intermediate material for manufacturing nut

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2158289A (en) * 1934-10-22 1939-05-16 Asea Ab Means for suppressing disturbances in ionic valves by grid control
SU139716A1 (ru) * 1958-09-08 1960-11-30 Е.М. Глух Независимый трехфазный инвертор
FR1373115A (fr) * 1963-08-06 1964-09-25 Ferodo Sa Dispositif onduleur polyphasé
US3198989A (en) * 1961-03-30 1965-08-03 American Mach & Foundry Electronic switch device with commutating capacitor
US3217207A (en) * 1961-05-26 1965-11-09 Elox Corp Michigan Peak drive protective circuit
GB1055855A (en) * 1964-05-22 1967-01-18 Alsthom Cgee Improvements in and relating to electric converters
US3449654A (en) * 1965-10-11 1969-06-10 Gen Motors Corp Direct current commutation system for brushless electrical motors

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1325853A (fr) * 1962-03-23 1963-05-03 Cem Comp Electro Mec Perfectionnement aux redresseurs et onduleurs non autonomes polyphasés
FR1439783A (fr) * 1964-07-17 1966-05-20 Elin Union Ag Redresseur de courant pourvu de moyens d'interruption rapide du courant en cas de dérangement

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2158289A (en) * 1934-10-22 1939-05-16 Asea Ab Means for suppressing disturbances in ionic valves by grid control
SU139716A1 (ru) * 1958-09-08 1960-11-30 Е.М. Глух Независимый трехфазный инвертор
US3198989A (en) * 1961-03-30 1965-08-03 American Mach & Foundry Electronic switch device with commutating capacitor
US3217207A (en) * 1961-05-26 1965-11-09 Elox Corp Michigan Peak drive protective circuit
FR1373115A (fr) * 1963-08-06 1964-09-25 Ferodo Sa Dispositif onduleur polyphasé
GB1055855A (en) * 1964-05-22 1967-01-18 Alsthom Cgee Improvements in and relating to electric converters
US3449654A (en) * 1965-10-11 1969-06-10 Gen Motors Corp Direct current commutation system for brushless electrical motors

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3867669A (en) * 1974-01-11 1975-02-18 Yakov Lvovich Krasik Power source with a sparkproof output
US3931546A (en) * 1974-05-28 1976-01-06 C. E. Niehoff & Co. Over-voltage protection circuit
US4331994A (en) * 1979-09-28 1982-05-25 Borg-Warner Corporation Shootthrough fault protection system for a voltage source transistor inverter
US4428023A (en) 1980-02-25 1984-01-24 Bbc Brown, Boveri & Company Limited Electronic protective circuit
US4825029A (en) * 1987-06-02 1989-04-25 Wickes Companies, Inc. Spark erosion system for reducing the height of a honeycomb seal
US4853046A (en) * 1987-09-04 1989-08-01 Surface Combustion, Inc. Ion carburizing
US5127967A (en) * 1987-09-04 1992-07-07 Surface Combustion, Inc. Ion carburizing
US5241152A (en) * 1990-03-23 1993-08-31 Anderson Glen L Circuit for detecting and diverting an electrical arc in a glow discharge apparatus
WO1999014779A1 (de) * 1997-09-16 1999-03-25 Siemens Aktiengesellschaft Anordnung zur gewinnung einer hilfsenergie für ein auslösesystem und verwendung derselben
US5995394A (en) * 1997-10-10 1999-11-30 Asea Brown Boveri Ab Device for connecting a VSC converter to a source of alternating voltage
US6442051B1 (en) 2000-10-31 2002-08-27 General Electric Company Full thyristor bridge circuit with free wheeling diode for de-excitation control and stability sensing

Also Published As

Publication number Publication date
FR2121514A1 (enrdf_load_html_response) 1972-08-25
DE2100415B2 (de) 1973-03-01
GB1373417A (en) 1974-11-13
SU1003777A3 (ru) 1983-03-07
JPS4714624A (enrdf_load_html_response) 1972-08-11
DE2100415A1 (de) 1972-07-20
CH546016A (enrdf_load_html_response) 1974-02-15
FR2121514B1 (enrdf_load_html_response) 1975-04-18
SE372673B (enrdf_load_html_response) 1974-12-23
IT946332B (it) 1973-05-21

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